Field of the Invention
The present invention relates to a method for controlling output energy of a power system, and in particular to a method for controlling output energy of a photovoltaic power system.
Description of Related Art
Sunlight is a well-known renewable energy source, and solar cells, as widely known, are designed to absorb sunlight and generate electric power. Typically, a solar energy system includes a plurality of solar cells disposed in an array or panel and a photovoltaic (PV) inverter connected to the solar cells to invert direct current (DC) power derived from the solar cells into alternative current (AC) power for connection to the utility.
In general, the solar energy system including solar cells and PV inverter mentioned above further includes a reactive power compensation device for improving power quality by controlling the reactive power and keeping the power factor as close to unity as possible.
However, the reactive power compensation device cause an overvoltage condition since the voltage inputted to the solar energy system is raised. Therefore it is desirable to use an energy recycle device to suppress overvoltage condition. The solar energy system includes the reactive power compensation device and energy recycle device, however, is bulky and the circuit thereof is complex.